Earbuds that are inserted into the wearer's ear canal, are commonly used with audio headsets that include a sound tube out of which sound is emitted. The earbud carries sound from the sound tube directly to the ear canal of the wearer while blocking sound from the environment. The earbud commonly includes a soft foam body with a through body passage, and a sleeve of stiffer material (usually solid material rather than foam) lying within the body. A sound tube such as one of an MP3 or IPOD-compatible speaker device is inserted into the sleeve, with the sleeve anchoring the sound tube to the body. The earbud is inserted into a person's ear and is retained by the press-fit of the foam body with the walls of the person's ear canal.
One way to produce an earbud is to mold or extrude the foam body with a passage, and to separately produce the sleeve. The sleeve is inserted into the foam body passage, with adhesive used to bond the sleeve and body together. Such a process requires the application of adhesive to the sleeve and/or body. It is common for bonding quality issues (adhesive strength, coverage, and cosmetics) to complicate and add cost to the manufacturing process. It is important that the earbud be manufactured consistently as a high-quality product at low cost. It would be desirable to minimize handling of parts and avoid the need for adhesive application, and make earbud manufacture a one-step process.